SMTP SMTP AUTH LOGIN RFC4954 # # Server-side REPLY EHLO 220 AUTH LOGIN REPLY AUTH 334 UGFzc3dvcmQ6 REPLY MTIzNA== 235 Authenticated # # Client-side smtp SMTP login authentication mail body smtp://%HOSTIP:%SMTPPORT/user --mail-rcpt 806@foo --mail-from 806@from -u test:1234 -T - # # Verify data after the test has been "shot" EHLO user AUTH LOGIN dGVzdA== MTIzNA== MAIL FROM:<806@from> RCPT TO:<806@foo> DATA QUIT mail body .